The number of plates in sewing machine fabric guides depend on the number of layers comprising the article being sewn and, more particularly, the number of plates must be such as to produce a number of parallel, superposed guide channels equal to the number of layers so that the layers can slide separately in these channels. It is essential to separate the layers to enable them to slide relative to one another and to automatically match the edges of the layers of the article being sewn. The plates which project beyond the vertical fabric guide wall may be stationary or movable in a vertical direction to vary the depth of the guide channels for the purpose of varying the thickness of the fabric. In the latter case, the vertical wall consists essentially of a series of vertical pins distributed along a path of travel forming an acute angle with the sewing axis.
According to known embodiments, the guide separating plates can also be moved sideways or can rotate to enable them to be moved away from the sewing zone to permit the passage of thicker sections of fabric such as pockets, loops, belts or other items which have been previously attached to the article.
The displacement of the plates can be controlled by suitable means such as pneumatic means actuatable by means of a push button, toggle switch or other suitable control means and it can also take place when the sewing machine is being operated.
It has been found that guides comprising plates capable of translational or rotational movements are subject to the disadvantage that during the step of reinserting them between the layers of fabric, particularly if this fabric consists of extremely flexible material, the movable plates bump against the edges of the layers, rolling them up without being inserted therebetween.